1. Field of the Disclosure
The present invention relates to fluid flow control for downhole tools.
2. Description of the Related Art
Control of fluid circulation can be of operational significance for numerous devices used in oil and gas wells. One illustrative example is a gravel packing tool used for gravel packing operations. In general, gravel packing includes the installation of a screen adjacent a subsurface formation followed by the packing of gravel in the perforations and around the screen to prevent sand from migrating from the formation to the production tubing. Usually, a slurry of gravel suspended in a viscous carrier fluid is pumped downhole through the work string and a cross-over assembly into the annulus. Pump pressure is applied to the slurry forcing the suspended gravel through the perforations or up against the formation sand. The gravel then accumulates in the annulus between the screen and the casing or the formation sand. The gravel forms a barrier which allows the in-flow of hydrocarbons but inhibits the flow of sand particles into the production tubing. Afterwards, a clean-up operation may be performed wherein a cleaning fluid is reverse circulated through the well to clean the tools of slurry and leaving only the gravel pack surrounding the screens behind.
The present disclosure provides methods and devices for controlling fluid circulation during gravel packing operations. The present disclosure also provides for controlling fluid circulation in other wellbore-related operations.